waves Flashcards
(53 cards)
transverse waves vibrate ……. to the direction of energy transfer
transverse waves vibrate perpendicular to the direction of energy transfer
longitudinal waves vibrate ……. to the direction of energy transfer
longitudinal waves vibrate ** parallel ** to the direction of energy transfer
what are the highest and lowest points of transverse waves?
highest - peak
lowest - trough
what are the highest and lowest points of longituodinal waves?
highest - compression
lowest - rarefaction
what is amplitude?
max displacement of a vibrating particle
wave frequency equation
frequency = 1/ time period
(time period = time for one complete cycle of a wave)
wave speed equation
V= f x λ
(wave speed = frequency x wave length)
what is the human auditory range?
20 - 20K Hz
what type of waves are sound and ultrasound waves?
longitudinal
what is ultrasound?
sound waves with a frequency higher frequency than 20k Hz
how can ultrasounds be used to see the internal structure of a object?
- ultrasound waves are reflected by boundaries in an object due to change in mediums
- if you know the wave speed and time it takes for the wave to be reflected you can calculate how far away the boundary is
what are seismic waves?
waves produced by an eathquake
what are the 2 types of waves produced when an earthquake happens?
surface waves - travel across the earth’s surface
body waves - travel through core of the earth
what are P waves and their properties?
primary waves
- longitudinal
- travel through solids and liquid (mantle, outer core and inner core)
- faster than s waves
what are S waves and their properties?
sheer waves
- transverse
- only travel through solids (mantle, can’t travel through outer core because it is liquid, so can’t reach inner core)
- slower
how have p and s waves helped work out the structure of the earth?
- refraction of p waves through the earth shows that the earth has different densities at different depths (presence of boundaries)
- s waves can’t travel through liquid so it not being able to travel through the outer core shows that it is liquid
angle of reflection = ?
angle of reflection = angle of incidence
how do smooth objects reflect light compared to irregular objects?
smooth - light reflected in all one direction (specular reflection)
irregular - scatters light in lots of directions (diffuse reflection)
when light travels from a denser medium to a less dense material what way does it refract?
away from the normal
what can happen to waves at the boundary between 2 materials? (4)
- reflection
- refraction
- absorption
- trasmission
when light travels from a less dense medium to a denser material what way does it refract?
towards the normal
what do waves transfer?
energy
(also info)
required practical
describe a practical to measure the speed of sound in air - variables?
IV: The distance between Person A and Person B.
DV: The time taken for the sound to reach Person B.
CV: The medium (air) through which the sound travels, the temperature and humidity of the environment (as they affect sound speed). The same method of creating the sound (e.g., striking the block).